Distribution of current onset voltage (COV) as well as threshold voltage (V_TH) and drain induced barrier lowering (DIBL) in MOSFETs fabricated by 65nm technology is statistically analyzed. Although V_TH distribution follows the normal distribution, COV and DIBL deviate from the normal distribution. It is newly found that COV follows the Gumbel distribution, which is known as one of the extreme value distributions. This result of statistical COV analysis supports our model that COV is mainly determined by the deepest potential valley between source and drain.